PITTSBURGH -- The Islanders had already clinched a playoff spot before they hit the ice on Friday. But there was still more to achieve -- not the least of which was a desire to shake off the sudden impact of Tuesday's last-second loss in Philadelphia.

Jaroslav Halak erased that bad memory with 37 saves, including 17 in a lopsided first period. The Islanders withstood the loss of Travis Hamonic to a suspected right knee injury that ended his night before the first period ended and pulled out a 3-1 win over the desperate Penguins, who will have to go to their final game on Saturday to try and secure a playoff berth.

The Islanders reached 100 points for the first time since the 1983-84 season and have secured a first-round matchup with the Capitals. If the Caps beat the Rangers on Saturday, the Isles will open the series in Washington; if the Caps lose in regulation, overtime or a shootout and the Islanders defeat the Blue Jackets on Saturfday, the series begins at Nassau Coliseum.

"We clinched [Thursday] and that was a little weight off our shoulders, but no matter what, we needed this game," said Brian Strait, whose point shot led to John Tavares' rebound goal 2:46 into the third period to break a 1-1 tie. "We talked about it before we went out there, that this was a playoff game, a game you have to win."

Halak got a bit of good fortune from officials in Toronto. On a power play at 7:52 of the first, Patric Hornqvist tried to stuff a backhand from behind the net .

Hornqvist finally flipped the puck up and onto Halak's glove before the goaltender pulled it back. The on-ice officials ruled no goal; replays showed the puck was likely over the goal line, but Halak's glove covered the goal line from the overhead camera and the video was ruled inconclusive, meaning the on-ice call stood.

Off the next faceoff, Cal Clutterbuck sent Casey Cizikas in on a shorthanded breakaway and Cizikas rippled the net over Marc-Andre Fleury's shoulder. In an eight-second span, the Isles went from likely down one to up a goal.

"I think they had cameras in the post tonight, too, but it wasn't conclusive," Halak said. "It was good for us it didn't go in."

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The Isles held their 1-0 lead until 5.7 seconds remained in the second period, when Syosset's Rob Scuderi swiped a loose puck off Halak and in to tie the score. But Tavares pounced on the rebound to silence the home crowd.

Even with just five defensemen for the final two periods, the Islanders were strong in their own end as the Penguins pressed for a tie. Michael Grabner turned on the jets to race down a puck and beat Fleury with 3:40 to go for the much-needed cushion.

"I thought we played phenomenal with our five D." said Jack Capuano, who had no update on Hamonic's injury, sustained when Scuderi crunched him along the boards. "Against a team like that when you lose someone like [Hamonic], it's tough to play. Overall we made good decisions."